Informix Error -254

Reasons / Common Causes

-254 is the embedded-SQL (ESQL/C) counterpart to -236's count-mismatch family — the number of host variables named in an INTO clause doesn't match the number of columns actually referenced in the statement.

1. A mismatch between the number of selected columns and the number of host variables listed in the INTO clause — fewer or more than needed.
2. A SELECT list edited (columns added or removed) without correspondingly updating the INTO clause's host variable list.
3. A typo or miscount when writing the INTO clause manually.
4. Using SELECT * without tracking the exact current column count, then providing a host-variable list that no longer matches after a later schema change.

Solutions / Resolution

1. Locate the statement (in a PREPARE or DECLARE) and verify the number of placeholders, per the official guidance.
2. Review the INTO clause's item list to find and correct the specific mismatch.
3. Prefer explicit column lists over SELECT * in embedded SQL, to avoid this fragility after future schema changes.
4. When a SELECT list changes, update the corresponding INTO clause in the same change — treat them as a matched pair that must move together.

Examples

The straightforward mismatch

EXEC SQL SELECT customer_id, name, email
  INTO :cid, :cname
  FROM customer WHERE customer_id = 1;
/* -254: 3 columns selected, only 2 host variables provided */

Fix:

EXEC SQL SELECT customer_id, name, email
  INTO :cid, :cname, :cemail
  FROM customer WHERE customer_id = 1;

A schema change breaking a previously-matching count

/* Originally 3 columns, 3 host variables — worked fine */
EXEC SQL SELECT id, name, status INTO :id, :name, :status FROM orders WHERE id = :oid;

/* After a later ALTER TABLE adds a column and this statement was
   changed to SELECT * without updating the host variable list */
EXEC SQL SELECT * INTO :id, :name, :status FROM orders WHERE id = :oid;
/* -254: orders now has 4 columns */

Diagnostic Checks

1. Count the columns in the SELECT list against the host variables in the INTO clause.
2. Review recent schema or select-list changes if this appeared unexpectedly on a statement that used to work.

Related Errors / Related Topics

• -236 — "Number of columns in INSERT does not match number of VALUES." The closest conceptual sibling — the same count-mismatch theme, applied to INSERT/VALUES rather than SELECT/INTO.
• -201 — "A syntax error has occurred." The general SQL-parsing-error family this fits into.

Treat the SELECT list and its INTO clause as a matched pair — any change to one requires an equivalent change to the other.